kirs

iter = Enumerator.new do |yielder|
  yielder.yield "start"
  3.times { |n| yielder.yield(n) }
  yielder.yield "end"
end

# iter.each do |n|
#   puts n
# end

kirs

$ curl -v https://js.pusher.com/4.0/pusher.min.js
*   Trying 23.111.9.14...
* TCP_NODELAY set
* Connected to js.pusher.com (23.111.9.14) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/cert.pem
  CApath: none

kirs

require 'active_support/callbacks'

class Job
  include ActiveSupport::Callbacks

  define_callbacks :perform

  set_callback :perform, :after, :save_omg

  def perform

kirs

# Updated for Ruby 2.3
string_t = None

def get_rstring(addr):
  s = addr.cast(string_t.pointer())
  if s['basic']['flags'] & (1 << 13):
    return s['as']['heap']['ptr'].string()
  else:
    return s['as']['ary'].string()

kirs

require 'bundler/setup'
require 'active_support/all'

module Feature
  extend ActiveSupport::Concern

  included do |base|
    puts "#{base} included Feature"
  end
end

kirs

Posts

How automatic deployment works

Our deployment tool, Shipit

Fighting flaky tests on CI

Testing Rails at scale, talk from RailsConf

kirs

require "net/http"
require "uri"

trap("TERM") do
  puts 'terminating...'
end

loop do
  begin
    http = Net::HTTP.new("www.google.com", 81)

kirs

Using strace and lsof to debug blocked processes

You can use strace on a specific pid to figure out what a specific process is doing, e.g.:

strace -fp <pid>

You might see something like:

select(9, [3 5 8], [], [], {0, 999999}) = 0 (Timeout)

kirs

Mixing posix threads and signal handling usually is a bit of a nightmare.

Ceri Storey, 2013

In what context is the signal handler executed?

Ruby executes the signal handler in the same thread as the parent. It can be proven by:

$stdout.sync = true

kirs

class Runner
  def initialize
    @count = 0
  end

  EXIT_AFTER = 5
  def perform
    loop do
      puts "Running #{@count}, shutdown: #{@shutdown.inspect}"
      @count += 1